1. Field of the Invention
The present invention relates generally to radio modems and host devices used in connection therewith, and more particularly to methods and apparatus for processing radio modem commands from a host device during a data communication session between the host device and a network server.
2. Description of the Problem
A radio modem typically includes a radio frequency (RF) transceiver for communicating with a wireless communication network and a host interface, such as an RS-232 interface, for connecting with a host device. In an AT command mode, the radio modem is able to receive, process, and respond to conventional AT commands from the host device. The AT command mode lets the host device obtain “real-time” radio-specific information, such as radio signal strength information and wireless network operator information, among other information, from the radio modem. On the other hand, in a network data session mode, the radio modem helps maintain a data communication session between the host device and a server of a communication network through an RF link. The data communication session may involve an Internet Protocol (IP) connection through which addressable data packets are passed back and forth between the host device and the network server.
During the data communication session, AT command processing between the host device and the radio modem is generally not available. Therefore, “real-time” radio-specification information cannot be easily obtained by the host device from the radio modem during the network data session. This information might be useful to the host device, for example, if the information were to be visually displayed (e.g. for visual display of a radio signal strength indicator or a wireless network operator identifier) or otherwise processed. It would be too complex and costly if additional interfaces were provided on the devices exclusively for AT command processing. Heroic techniques (e.g. breaking into the data session link, sending command and response information, and reestablishing the data session link) are complicated, prone to failure, and require modification of the host device's data session protocol.
Accordingly, there is a resulting need for methods and apparatus for processing radio modem commands during network data sessions.